Offset half ring molybdenum gun liners



Jan. 21, 1958 s. OMENETZ 2,820,399

OFFSET HALF RING MOLYBDENUM GUN LINERS Filed Nov. 5, 1952 2 Sheets-Sheet l uvvm ro GEORGE VCQMEN Z ATTORNEYS Jan. 21, 1958 e. COMENETZ OFFSET HALF RING MOLYBDENUM GUN LINERS 2 Sheets-Sheet 2 Filed-Nov. 5, 1952' INVENTOR; GEORGE COMENETZ BY %Q@,.;

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ATTORNEYS [lit OFFSET HALF RDJG MOLYBDENUM GUN LINERS Application November 5, 1952, Serial No. 318,941

4 Claims. (Cl. 8916) This invention relates to wear resistant liners and more particularly to liners for guns.

It has been the practice in the past to line certain gun barrels with molybdenum liners in the form of a series of rings. Rings have been employed since molybdenum has not been available in the form of long cylinders possessing optimum tensile properties although short rings have such properties. As a projectile passes through the bore of the gun forces are present which tend to move the rings forwardly in the barrel, and due to the rifling, the rings tend to rotate in the barrel. Shrink fitting alone will not prevent this movement since the coeificient of thermal expansion of molybdenum is less than that of steel and hence they become loose in their surrounding steel carrier, or barrel, when the gun has attained an elevated temperature as a result of continued firing. The rings must therefore be keyed against forward motion and rotation more efiectively than by shrink fitting. One of the constructions employed in the past to prevent the foregoing movements has been the provision of molybdenum rings each having a surrounding annular steel band, the steel band being shrink fitted within the carrier and the molybdenum ring keyed to the band, usually by pins extending lengthwise, partly disposed within the band and partly within the ring. With this construction the steel bands remain tight in the carrier at elevated temperatures since they have the same coeflicient of thermal expansion as the steel carrier or barrel. With this construction it has been found, however, that after considerable firing cracks develop in the molybdenum rings and in some cases extend completely through same where the locking pins are disposed, and especially toward the breach end of the liner. In some cases fragments of the liner become detached thus ending the life of the gun. The cracking referred to has been attributed, at least in part, to the relatively high notch sensitivity of molybdenum.

One of the objects of this invention is to provide a molybdenum gun liner constructed of a plurality of armate portions of rings rather than integral annular rings as have previously been employed.

Another object is to provide a construction which obviates keying notches or the like from which cracks may start and grow.

A further object is to provide a shrink fitted steel sleeve within a steel gun barrel which will remain tight within the latter at elevated temperatures and which serves as a keying member for the arcuate molybdenum portions of the liner without the use of objectionable notches in the molybdenum portions.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. l is a perspective of the assembly of half rings employed in one embodiment of the invention;

Fig. 1A is an exploded view of the three dilferent half rings employed in the assembly of Fig. l;

ates Patent 2,8 ,399 Patented Jan. 21, 1958 Fig. 2 is a perspective of a retaining sleeve for the half ring assembly of Fig. 1;

Fig. 3 is a longitudinal central section through a tubular carrier member, such as a gun barrel, showing a simplified form of the invention in side elevation, the retaining sleeve being broken away to the plane of the longitudinal section of the tubular member;

Fig. 4 is a section taken on line 44, of Fig. 3;

Fig. 5 is a section taken on line 5-5, Fig. 3;

Fig. 6 is a side elevation of the half ring retaining sleeve of Fig. 5, as viewed in the direction of arrow 6, portions being broken away;

Fig. 7 is a section taken on line 77, Fig. 6;

Fig. 8 is a section taken on line 8-8, Fig. 6;

Figs. 9, 11 and 13 are end elevations of half rings employed in Fig. 3; and

Figs. 10, 12 and 14 are side elevations of the rings of Figs. 9, 11 and 13, respectively.

Referring in detail to the drawing, and particularly Figs. 9 to 14, half rings 20, 21 and 22 all have the same inside diameter D. Half rings 20 and 21 have the same outside diameter D but differ in that the length 2L of half ring 21 is twice the length L of half ring 2%. Half ring 22 has a larger outside diameter D than half rings 20 and 21 and the same length 2L as half ring 21.

Referring to Figs. 6 to 8, the half ring retaining sleeve 23 has an inside diameter D the same as the outside diameter of half rings 20 and 21 and an outside diameter D the same as the outside diameter of half ring 22. Two diametrically opposite rows of semi-circular slots 24 are provided in the wall of the sleeve, the slots of one row being staggered with respect to the slots of the other row. The width 2L of these slots is the same as the length of half rings 21 and 22.

Figs. 3 to 5 illustrate the arrangement of the various half rings in the sleeve. In the assembly of the parts, half rings 20, and 21 are slid into the sleeve in an axial direction and half rings 22 inserted radially inwardly into slots 24 to form an assembly, as shown in Fig. 3. The assembly is then shrink fitted in the bore of a carrier member 25 which may be a gun barrel or other encasing member. The shrink fit on the sleeve prevents it from rotating or moving axially which in turn prevents rotation or axial movement of half rings 22 which are locked within their retaining slots 24. As will be apparent, the remaining half rings are locked against axial movement since they fill the axial space between opposed side faces of adjacent aligned half rings 22 of a row and are locked against rotation by the abutment of their ends with ends of half rings 22 of a diametrically opposite row, portions of ends of half rings 21 of each row abutting ends of half rings 22. The half ring and sleeve assembly may be made in any desirable length or a plurality of sleeve assemblies may be disposed in tandem relationship.

When member 25 is the barrel of a gun the construction shown in Figs. 1 and 3 will usually be preferred. This construction is the same as that previously described except that the ends of slots 24a and the ends of the half rings 20a, 21a and 22a are ruled surfaces, rather than flat surfaces, so that they join along opposite helices H having the same twist as the gun rifiing, which latter is machined in the liner bore.

While a construction has been illustrated and described in which half rings are employed it will now be apparent that quarter rings or rings of any angular extent may be employed so that the number of helices H corresponds to the number of lands of the rifling. It will also be apparent that fewer of the half rings 22 or 22a may be employed as compared to half rings 21 or 21a in the respective embodiments. Many other modifications and variations of the present invention will become apparent to those skilled in the art in the light of the above teach- 3 ings and it is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically illustrated and described.

What is claimed is:

l. A gun barrel comprising: a steel carrier having a bore therein, a steel liner shrink fitted within said bore, said liner having opposite rows of semi-circular axially spaced staggered slots extending through the wall thereof, a plurality of semi-circular liner members disposed within said sleeve with their outer surfaces in engagement with the inner surface of said sleeve, a plurality of liner members disposed in and filling said slots having portions extending inwardly of the inner surface of said sleeve engaging portions of certain of the first named members and adapted to prevent axial movement and rotation of the first named members within said sleeve, the inner surfaces of said liner members forming the projectile bore of the gun, said projectile here being rifled, said liner members being of a metallic material having a coefiicient of thermal expansion less thanthat of steel.

2. A gun barrel comprising: a steel carrier and a sleeve shrink fitted therein, a plurality of semi-circular liner members disposed entirely within the sleeve, and a plurality of similar semi-circular liner members disposed partly within the sleeve and partly within axially spaced staggered slots in the wall of the sleeve, opposite ends of each of the last named members engaging portions of the ends of a pair of juxtaposed first named members and preventing rotation of same, each juxtaposed pair of members being disposed between and filling the space between a spaced pair of second named members.

3. A liner comprising: a cylindrical sleeve having a semi-circular slot through the wall thereof, said slot having confronting radially extending parallel faces and diametrically opposite ends, a semi-circular liner members disposed within and filling said slot having portions of its ends disposed within the sleeve, and a pair of adjacent semi-circular liner members disposed within the sleeve, each having ends abutting said portions, the inner surface of said first and second members forming a cylindrical bore, the construction and arrangement being such that when the first named member is restrained from out ward movement in the slot containing same, said portions prevent rotation of the second named members within the sleeve.

4. A liner comprising: a cylindrical sleeve having two longitudinally extending rows of semi-circular slots through the wall thereof, the slots of one row being staggered with respect to the slots of the other row, a plutrality of semi-circular line members, each being disposed within and filling a slot and having opposite annular faces disposed within the sleeve, a plurality of semi-circular liner members disposed within the sleeve and filling the spaces between annular faces of the first named members; and a carrier having a bore therein with a cylindrical surface in which said liner is disposed, the outer surfaces, said first named members and the outer surface of said sleeve engaging said cylindrical surface.

References Cited in the file of this patent UNITED STATES PATENTS 773,935 Hallock Nov. 1, 1904 1,746,020 Whitely Feb. 4, 1930 2,238,670 Traversi Apr. 15, 1941 2,499,944 Brace Mar. 7, 1950 

